Question

我创建了具有图片的简单UIScrollView。每次按下图像我想要更改该图像时，我该怎么办？

我创建了这个UIScrollView并使用带有图片的NSMutableArray初始化它。

      UIScrollView *myScroll = [[UIScrollView alloc] initWithFrame: CGRectMake (0,100,200,30)];
        NSMutableArray = *images = [NSMutableArray alloc] initWithObjects: img1,img2,img3,nil];

for (int i=0; i<3; i++)
{
        UIImageView *imageV = [UIImageView alloc];
        [imageV setImage:[images objectAtIndex:i]];
        [myScroll addSubview:imageV];
        [imageV release];
}


    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget: self action:@selector (changeImg:)];
    [myScroll addGestureRecognizer: singleTap];

并且我正在摸着卷轴上的触摸位置：

- (void) singleTapGestureCaptured:(UITapGesturerecongnizer *) gesture
{
    CGPoint touch = [gesture locationInView:myScroll];

}

通过X，触摸项目的Y，我知道选择了什么图像

这里我需要更改myScroll的第一张图片......我该怎么做？

Answer 1

您的应用程序将崩溃，因为您正在访问索引3，但索引3处没有任何对象。

UIScrollView *myScroll = [[UIScrollView alloc] initWithFrame: CGRectMake (0,100,200,30)];
NSMutableArray = *images = [NSMutableArray alloc] initWithObjects: img1,img2,img3,nil];
[myScroll addSubview:[images objectAtIndex:0];
[myScroll addSubview:[images objectAtIndex:1];
[myScroll addSubview:[images objectAtIndex:2];

现在您可以使用tagValue

访问图像视图

-(void)changeImg :(UIGestureRecognizer*)recog
{
    UIScrollView *scroll = (UIScrollView*)recog.view;
    CGPoint point = scroll.contentOffset;
    int imagetag = (point.y/scroll.frame.size.height);

    UIImageView *image=(UIImageView*)[[scroll subviews] objectAtIndex:imagetag];
    NSLog(@"Image tag = %d",image.tag);

    image.image=[UIImage imageNamed:@"Icon-72.png"];
}

Answer 2

在UITapGestureRecognizer上添加UIImageView并默认为userInractionEnabled:设置YES NO UIImageView。

UIScrollView *myScroll = [[UIScrollView alloc] initWithFrame: CGRectMake (0,100,200,30)];
NSMutableArray = *images = [NSMutableArray alloc] initWithObjects: img1,img2,img3,nil];

for (int i=0; i<3; i++)
{
    //In your question you didn't set `imageView` frame so correct it
    UIImageView *imageV = [[UIImageView alloc]initWithFrame:yourFrame];
    [imageV setImage:[images objectAtIndex:i]];
    [imageV setUserInteractionEnabled:YES];
    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget: self action:@selector (changeImg:)];
    [imageV addGestureRecognizer: singleTap];
    [myScroll addSubview:imageV];
    [imageV release];
}

成功添加所有imageView后，您可以点击这样： -

-(void)changeImg:(id)sender
 {
     UIGestureRecognizer *recognizer = (UIGestureRecognizer*)sender;
     UIImageView *imageView = (UIImageView *)recognizer.view;
     [imageView setImage:[UIImage imageNamed:@"anyImage.png"]];
 }

Answer 3

一个简单的实现将是，如果你使用自定义按钮并在其IBAction上更改其图像..仍然你可以添加Gesture到你的UIImageView和

if(recognizer.state == UIGestureRecognizerStateBegan)

您可以在运行时更改图像。我希望这有帮助。干杯!!

在所选项目上替换UIScrollView中的图像

3 个答案: